Multiple-pin plug and socket couplings



July 17, 1956 J. E. s. CHAPMAN 2,755,450

MULTIPLE-PIN PLUG AND SOCKET COUPLINGS Filed June 13, 1950 2 Sheets-Sheet l I n ven tor Joaey bfdward vaffrey Chapman A ttorneys J. E. G. CHAPMAN MULTIPLE-PIN PLUG AND SOCKET COUPLINGS July 17, 1956 2 Sheets-Sheet 2 Filed June 13, 1950 Inventor ffi'e (773771774!) %%Jf Attorney 5 d 1. II u T nw 44 4 I1 LLCKC MULTIPLE=P1N PLUG AND SOCKET CQUPLINGS Joseph Edward Geoffrey Chapman, Workington, Cumberland, England, assignor to British Insulated Callenders Cables Limited, London, England, a British company Application June 13, 1950, Serial No. 167,761

Claims priority, application Great Britain December 1, 1949 12 Claims. (Cl. 33964) This invention relates to detachable two-part multiple conductor couplings of the kind in which the parts comprise moulded bodies of inelastic insulating material, in one of wlL'ch bodies are partially embedded a multiplicity of pin contacts which are adapted to enter and make electrical connection with a corresponding number of socket contacts which are held in the other moulded body of inelastic insulating material, when the two parts of the coupling are brought into engagement. The term inelastic is here used to mean not having the property of soft rubber and rubber-like materials of stretching readily under light loads. In some cases it is found that although the pins and sockets may be accurately spaced for proper engagement at the beginning of the moulding operation, subsequent shrinkage of the moulded insulating material in which the contacts are held causes a disturbance of the spacing of the pins and also of the spacing of the sockets, with the result that when it is required to bring the pins and sockets into engagement difliculty is experienced in doing so. In some cases the disturbance of the spacing is such that very considerable pressure is required in order to force the pins into their respective sockets.

In the specification of the co-pending application No. 167,744, filed lune 13, 1950, it is indicated that the difficulty in making and breaking the coupling that is caused by such shrinkage of the moulded insulating material can be avoided, in accordance with the invention there disclosed, by arranging that when the two parts of the couplings are fully in engagement there is a substantial length of the unembedded portion of each pin contact which is laterally unsupported by the moulded insulating material. The term substantial length is used to indicate a length somewhat less than, equal to, or greater than the axial length of the socket engaging part. It is explained that this construction generally provides sufficient resiliency between the interengaging portions of the pin and socket contacts to compensate for any inaccuracies of spacing set up by the shrinkage of the insulating material, so that no difiiculty is experienced in bringing the two parts of the coupling into proper engagement, but that greater resiliency may be obtained by making the unsupported portions of the pins of smaller cross-section than the socket-engaging portions.

We have now found that the resiliency obtained by the above described construction is generally more than adequate to overcome the effects of misalignment of some of the contacts due to shrinkage of the body in which they are moulded and by the present invention we make use of this excess resiliency to ensure maintenance of adequate contact pressure between all pins and their respective sockets throughout the working lif of the coupling. This we do by so positioning the pins and sockets, during the process of moulding them in the insulating material, as to provide for a controlled degree of misalignment between the socket engaging part of each pin and its respective socket. This misalignment, which is additional to, or is sufficient to overcome the effect of,

Patented July 17, 1958 any inadvertent misalignment of certain pins and their sockets resulting from inequalities in shrinkage of the moulded bodies, ensures that in the fully engaged position the unembedded part of each pin is elastically laterally deflected from its natural position with respect to its embedded part. As a consequence, each contact memher is pressed firmly into contact with a part of its cooperating contact, thus permitting the use of solid pins and inexpansible sockets, which are respectively cheaper than split pins and split sockets.

The invention will be more fully described with the aid of the accompanying drawings wherein Figures 1 and 2 are fragmental sections showing two ways of arranging for a substantial length of each pin contact to be left laterally unsupported by the molded body by which it is held,

Figure 3 is a view partly in elevation and partly in section of an example of a two-part cable-to-cable coupling constructed in accordance with the invention,

Figures 4 and 5 show means for supporting contacts during the operation of making the moulded body in which they are held,

Figure 6 is a fragmental view showing a preferred form of socket contact,

Figures 7 and 8 are diagrammatic sections of two examples of coupling of which the contacts are so moulded in as to provide for a controlled degree of misalignment of each pin with its respective socket,

Figure 9 is a fragmental section on the line IX--IX in Figure 7 and Figure 10 illustrates a modified form of two-part coupling in which the contacts of one or both parts are elastically stressed when the parts are mated.

As is shown in Figure 1 of the drawings, the whole of the unembedded portion of each pin contact 1 projects beyond the end face of the moulded body 3 in which the contact is held embedded. This projecting part of each pin contact 1 is approximately twice the axial length of the socket of the socket contact 2 which receives it. This leaves a substantial length of the projecting part of the pin contact, namely, the rear half, unsupported laterally either by the moulded body 3 in which it is held or by the moulded body 4 in which the socket is embedded. The moulded body 3 is moulded in a metal casing 5 and the body 4 in a metal casing 6 which is secured to the casing 5 by a captive nut 7. The same result may be achieved if a part of each pin contact that lies between the socket engaging part of the embedded portion lies in a recess in the face of the moulded body, the recess being of greater diameter than the part of the contact lying Within it, thereby providing an annular clearance 8 between a part of each pin contact 1 and the surrounding moulded body 3 of insulation in which the contact is held, as shown diagrammatically in Figure 2 of the drawings.

Still greater resiliency may be obtained, when necessary or desirable, by making a part of each pin contact that lies between the socket engaging part and the embedded portion, of reduced cross-section as compared with the socket engaging part, as shown at 1a in Figure 1.

The two-part cable-to-cable coupling shown in Figure 3 is designed for coupling together two lengths of screened multiple conductor polyethylene insulated cable, 19a and 10b. The socket part Illa of the coupling comprises a number of socket contacts 2 to the rear ends of which are connected to tail ends 12a of the conductors of cable length 10a. The socket contacts and their conductors are embedded in a mass of polyethylene 14a moulded in a funnel shaped metal sleeve 15a, the front ends of the sockets being flush with the end face 16a of the polyethylene moulding. The metal braid screen 17a of the cable length a is clamped to the rear end of the sleeve a by a clamping ring 18a. This and the neighboring part of the sleeve is enclosed in an outer moulding 19a of polyethylene which is protected by a rubber muff Ztla of which the smaller end grips the cable 10a. The other part 11b of the coupling is similar to the first part as so far described (except that the contacts are pin contacts) and corresponding parts have been given corresponding reference numerals, accompanied by the suffix b. As will be seen the pins 1 project beyond the end face of the moulding in which they are held by a distance approximately equal to twice the axial length of the sockets of the socket contacts 2 which receive them.

The socket contacts of the part 11a are protected by a shroud 22a formed by the front end of the sleeve 15a which projects beyond the front face of the moulding 14a. The pins of the other part are similarly shrouded but in this case the internal surface of the shroud 22b which is of greater axial length, is stepped to provide a joint face 23b for engagement by the end face 23a of the shroud 22a of the first part when the two parts are mated. Preferably a rubber sealing ring 24 is placed in a groove in the face 23b. The external surface of the forward end of the shroud 22b is crew threaded and a captive nut 25 is provided on the sleeve 15a so that the two coupling parts may be pulled together and held in the mating position. In this position each pin is left laterally unsupported for about half its projecting length. It has been found that with this form of coupling, even when there are no less than twenty-three pairs of contacts, in spite of the disturbance in the spacing of the pins and sockets caused by shrinkage of the moulded insulating material, satisfactory engagement of the pins and sockets can be readily obtained without the exertion of considerable force.

To ensure registration of the two parts a key 26 is fitted on the front end of the sleeve 15a of the socket part of the coupling and a key-Way 27 is cut in the internal surface of the shroud 22b of the other coupling part.

For some purposes it is desirable to screen certain contacts or groups of contacts from other contacts or groups of contacts. To this end metal screen plates 23a, 28b may be provided. These are embedded in the mouldings, each of the screens 28a, and 23!), extending rearwardly far enough to overlap axially the cut-back tubular braids 29a, 2%, respectively, which screen the individual conductors 12a, 121') from one another, and extending forwardly to a point that is flush with the front face 23a of the shroud 22a or the joint face 23b, as the case may be, so that when the two parts 11a and 11b are mated, the front edges of the screen plates 28a, 28b abut or almost abut.

During the operation of moulding-in the contacts they are positioned by means of a jig which forms a wall of the mould casing, the sleeve 15a or 15b forming the remaining part of the mould casing. As will be seen in Figure 8 the jig consists of a metal block 30 which fits in the shroud portion of the sleeve 15b and is angularly positioned relative to the sleeve by being provided with a key 31 which fits the key-way 27 of the sleeve. In the block are a number of appropriately spaced holes 32 for the reception of the projecting portions of the pin contacts 1 of which for the sake of simplicity of drawing only two are shown. The same block 30 may be used to form a jig to support the socket contacts 2, in which case the holes in the block are fitted with dowels 33 which support the socket contacts during the moulding operation, as shown in Figure 5. In this case the angular position of the jig relative to the sleeve 15:: is controlled by a sleeve 34 provided with a key-way 35 which receivm the key 31 on the block 30 and the key 26 on the sleeve 15a.

The sockets of the socket contacts 2 are shown with slit walls which are reinforced by a spring sleeve 36 as fit 4 shown more clearly in Figure 6 (which is drawn to a larger scale than Figure 3) and each dowel 33 has a diameter equal to the diameter of the part of the pin which enters the socket. Consequently, during the operation of moulding-in the socket contacts, the sockets of these contacts are held to the same diameter to which they are held by the pin contacts when the coupling is made. After the completion of the moulding operation and withdrawal of the dowel pins, the sockets close to their minimum working dimensions. As the socket wall of the socket contacts do not adhere to the polyethylene moulding a tiny gap appears round each socket wall into which the socket contact can expand when its pin is inserted.

Where, in accordance with the present invention a controlled degree of misalignment of each pin with respect to its respective socket is provided to ensure that each pin contact member is pressed firmly into contact with a part of its cooperating socket contact, the sockets need not have slitted walls. For providing a controlled degree of misalignment, jigs can be used to position the contacts during the moulding-in operation, which hold each contact of one (or both) of the coupling parts out of its nominal position by an appropriate amount. Where the two parts of the coupling are provided with a registering device positively preventing the rotation of one part relative to the other, the pattern of the contacts of one coupling part may lie at a very small angle to that of those of the other parts, whereby each contact of at least one part is elastically deflected in a circumferential direction with respect to the axis of the coupling. As shown in Figure 11 for instance, each pin contact 1 on one coupling part may be slightly displaced in a clockwise direction (looking through the plug part to the socket part of the coupling) from its nominal position and each socket contact 2 on the other coupling part slightly displaced in a counter-clockwise direction from its nominal position, so that each pin is out of alignment with its socket to an extent equal to twice the displacement referred to. Where the nominal pattern of contacts is symmetrical about a plane containing the axis of the couplings this may be conveniently achieved by the use of a single jig of the type described with reference to Figures 8 and 9 for the contacts of both parts of the coupling, the holes 32 in the jig block 30 being bored slightly oif their nominal position.

Instead of being displaced circumferentially from the nominal position the pins of one coupling part or the sockets of the other may be slightly displaced relative to one another in directions radial to the axis of the coupling, in which case a registering device is not necessary. However separate jigs would be required for positioning the contacts when moulding the two parts of the coupling.

A preferred form of displacement from the nominal position is shown in Figure 8, where the contacts are arranged in groups of four, the contacts of each group being nominally placed at the corners of a square. The socket contacts 2 are shown as being in their nominal positions; two diagonally opposite pin contacts of each group as displaced outwards from and the other two as displaced inwards towards the centre of the group. In practice however the displacement would be shared equally between the two sets of contacts so as to permit both sets of contacts to be moulded-in with the aid of a single jig block 30 when the directions and magnitudes of the displacements of the contacts of the left hand group of four are made the same as those of the right hand group of four. The reason for this will be apparent if it is borne in mind that the pins positioned for the moulding-in operation in the holes of left hand group of holes in the jig block engage the sockets positioned for the moulding-in operation on the dowels in the holes of the diametrically opposite group of holes in the jig block. This form of displacement has the advantage that it does W not depend upon the key 26 for maintenance of the misalignment.

Naturally, instead of the forms of misalignment indicated other forms may be adopted, for example, a combined radial and circumferential displacement from the nominal, or the contacts of one coupling member may be set at a slight angle to the axis of the coupling.

The degree of misalignment required to provide for satisfactory contact pressure will depend upon the size and form of contact used, and can readily be determined for each case. It will be appreciated that this misalignment is greatly exaggerated in Figures 7, 8 and 9. In the case of a coupling comprising circular pins secured, parallel to the axis of the coupling, in a moulding of polyethylene and havin each a projecting length of about one inch of which about one half only enters a socket of which the entire length is embedded in a moulding of polyethylene, where the pins have a diameter of about one tenth of one inch a combined degree of misalignment of 0.01 inch has been found to be satisfactory.

it will be understood that the leading end of each pin will be rounded off, and the entrance to each socket enlarged, to facilitate engagement of the misaligned contacts, as is shown in Figure 9.

in a modification we provide for the elastic lateral deflection of the pin contacts of the coupling by means of a registering device which imparts a slight relative rotation of one part to the other as the two parts are moved axially towards one another from an initial position of partial engagement of pins and sockets to a final position of full engagement. For instance, as shown in Figure 10, a non-circular central projection 37 on one coupling (say, the socket) part may enter a corresponding aperture in the other part, the projection being of slightly twisted form, or a projection at the circumference of one coupling part may take in a slot of slightly helical form in the circumferential surface of the other coupling part. For instance the key 26 of the coupling of Figure 7 may be made short and the key-way 27 be made slightly helical instead of being parallel with the axis of the coupling.

Vhat I claim as my invention is:

l. A detachable two-part multiple pin and socket coupling comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts held by being embedded in one of said bodies, a corresponding number of socket contacts each embedded substantially throughout the length of its socket portion in the other of said bodies, a substantial length of the pin contact of each pair of engaged contacts being, when the two parts of the coupling are fully engaged, left laterally unsupported by the moulded insulating. material and the socket engaging part of each pin contact being elastically deflected laterally from its natural position with respect to its embedded portion due to the presence of a controlled degree of misalignment between each pin contact and its respective socket contact.

2. A detachable two-part multiple pin and socket coupling comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts arranged in a pattern and having portions embedded in one of said bodies, a multiplicity of socket contacts arranged in a pattern and having substantially the whole of their socket portions embedded in the other of said bodies, the pattern of the embedded parts of said pin contacts differing slightly from the pattern of the embedded parts of said socket contacts, whereby when the two parts of the coupling are fully engaged the socketengaging part of each pin contact is elastically deflected with respect to its embedded portion, a substantial length of each elastically deflected pin contact being laterally unsupported by the moulded insulating material.

3. A detachable two-part multiple pin and socket coupling comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of pin contacts arranged in a pattern and having portions embedded in one of said bodies, a multiplicity of socket contacts arranged in a pattern and having socket portions at least substantially fully embedded in the other of said bodies, means for registering one coupling part angularly relative to the other coupling part whereby when the two coupling parts are fully engaged the pattern of the socket contacts of one part lies at a very small angle to the pattern of the embedded portions of the pin contacts of the other part whereby the socket engaging part of the pin contact of each pair of contacts is elastically deflected with respect to the embedded portion in a circumferential direction with respect to the axis of the coupling, a substantial length of each elastically deflected pin contact being laterally unsupported by the moulded insulating material.

4. A detachable two-part multiple pin and socket coupling comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts arranged in a nominal pattern and having portions embedded in one of said bodies, a multiplicity of socket contacts arranged in the same nominal pattern and having socket portions at least substantially fully embedded in the other of said bodies, the nominal pattern of the contacts of the two parts being symmetrical about a plane containing the axis of the coupling, and the axes of the embedded portions of the contacts of each co-operating pair of contacts being displaced in opposite directions from their nominal positions whereby when the two parts of the coupling are fully engaged, the socket-engaging part of the pin contact of each pair of contacts is elastically laterally deflected with respect to the embedded portion of the pin contact, a substantial length of each elastically deflected pin contact being laterally unsupported by moulded insulating material.

5. A detachable two-part multiple pin and socket coupling, comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts having portions embedded in one of said bodies, a corresponding number of socket contacts having socket portions at least substantially fully embedded in the other of said bodies, one of said bodies having helically extending surfaces and the other of said bodies having surfaces engageable with said helically extending surfaces to form a registering device for imparting a slight relative rotation of one coupling part to the other when the two parts are moved axially toward one another from an initial position of partial engagement of pins and sockets to a final position of full engagement, in which final position a substantial length of the laterally elastically deflected unembedded portion of each pin contact is left laterally unsupported by moulded insulating material.

6. A detachable two-part multiple pin and socket coupling comprising a pair of moulded bodies of inelastic insulating material, a multiplicity of moulded-in socket contacts located in one of said said bodies and each comprising a socket portion lying substantially Wholly within and closely surrounded by said one of said bodies, and a multiplicity of elastically deflectable pin contacts, each comprising a portion embedded in the other of said bodies and an adjoining uncmbedded portion which includes a socket-engaging part and has a length approximately at least equal to twice the axial length of the socket-engaging part, said socket-engaging part of each pin contact being elastically deflected with respect to the embedded portion of the pin contact when the two parts of the coupling are fully engaged, due to the presence of a controlled degree of misalignment between each pin contact and its respective socket contact.

7. A detachable two-part multiple pin and socket coupling comprising a pair of molded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts held by being embedded in one of said bodies and having socket-engaging parts of solid circular section, a corresponding number of socket contacts each embedded substantially throughout the length of its socket portion in the other of said bodies, a substantial length of the pin contact of each pair of engaged contacts being, when the two'parts of the coupling are fully engaged, left laterally unsupported by the molded insulating material and the socket-engaging part of each pin contact being out of alignment with its respective socket when the two parts of said coupling are in alignment but out of engagement, whereby when the two parts are fully engaged, the socketengaging part of each pin contact is elastically deflected laterally from its natural position with respect to its embedded portion.

8. A detachable two-part multiple pin and socket coupling comprising a pair of molded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts arranged in a pattern and having portions embedded in one of said bodies and socket-engaging portions of solid circular section, a multiplicity of socket contacts arranged in a pattern and having substantially the whole of their socket portions embedded in the other of said bodies, the pattern of the embedded parts of said pin contacts diiiering slightly from the pattern of the embedded parts of said socket contacts, whereby when the two parts of the coupling are fully engaged the socketengaging part of each pin contact is elastically deflected with respect to its embedded portion, a substantial length of each elastically deflected pin contact being laterally unsupported by the molded insulating material.

9. A detachable two-part multiple pin and socket coupling comprising a pair of molded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts arranged in a pattern and having portions embedded in one of said bodies and socket-engaging portions of solid circular section, a multiplicity of socket contacts arranged in a pattern and having socket portions at least substantially fully embedded in the other of said bodies, means for registering one coupling part angularly relative to the other coupling part whereby when the two coupling parts are fully engaged the pattern of the socket contacts of one part lies at a very small angle to the pattern of the embedded portions of the pin contacts of the other part whereby the socket-engaging part of the pin contact of each pair of contacts is elastically deflected with respect to the embedded portions in a circumferential direction with respect to the axis of the coupling, a substantial length of each elastically deflected pin contact being laterally unsupported by the molded insulating material.

10. A detachable two-part multiple pin and socket coupling comprising a pair of molded bodies of inelastic r insulating material, a multiplicity of elastically deflectable pin contacts arranged in a nominal pattern and having portions embedded in one of said bodies and socket-engaging portions of solid circular section, a multiplicity of socket contacts arranged in the same nominal pattern and having socket portions at least substantially fully embedded in the other of said bodies, the nominal pattern of the contacts of the two parts being symmetrical about a plane containing the axis of the coupling, and the axes of the embedded portions of the contacts of each co-operating pair of con tacts being displaced in opposite directions from their nominal positions whereby when the two parts of the coupling are fully engaged, the socket-engaging part of the pin contact of each pair of contacts is elastically laterally deflected with respect to the embedded portion of the pin contact, a substantial length of each elastically deflected pin contact being laterally unsupported by molded insulating material.

11. A detachable two-part multiple pin and socket coupling, comprising a pair of molded bodies of inelastic insulating material, a multiplicity of elastically deflectable pin contacts having portions embedded in one of said bodies and socket-engaging portions of solid circular section, a corresponding number of socket contacts having socket portions at least substantially fully embedded in the other of said bodies, one of said bodies having helically extending surfaces and the other of said bodies having surfaces engageable with said helically extending surfaces to form a registering device for imparting a slight relative rotation of one coupling part to the other when the two parts are moved axially towards one another from an initial position of partial engagement of pins and sockets to a final position of full engagement, in which final position a substantial length of the laterally elastically deflected unembedded portion of each pin contact is left laterally unsupported by molded insulating material.

12. A detachable two-part multiple pin and socket coupling comprising a pair of molded bodies of inelastic insulating material, a multiplicity of molded-in socket contacts located in one of said bodies and each comprising a socket portion lying substantially wholly within and closely surrounded by said one of said bodies, and a multiplicity of elastically deflectable pin contacts, each comprising a portion embedded in the other of said bodies and an adjoining unembedded portion which includes a socketengaging part of solid circular section and has a length approximately at least equal to twice the axial length of the socket-engaging part, said socket-engaging part of each pin contact being out of alignment with its respective socket when the two parts of said coupling are in alignment but out of engagement, whereby when the two parts are fully engaged, the socket-engaging part of each pin contact is elastically deflected with respect to the embedded portion of the pin contact.

References Cited in the file of this patent UNITED STATES PATENTS 1,652,708 DeLeeuw Dec. 13, 1927 2,069,375 Lane Feb. 2, 1937 2,229,211 Korengold Jan. 21, 1941 2,440,279 Larkius Apr. 27, 1948 2,638,573 Glickman May 12, 1953 FOREIGN PATENTS 345,116 Great Britain Mar. 19, 1931 525,325 Germany May 22, 1931 

